package com.review.test;

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * @param node TreeNode类 二叉树root节点
     * @return int整型一维数组
     */
    public int[] TreeBFS(TreeNode node) {
        // write code here
        if (node==null){
            return new int[]{};
        }

        ArrayList<Integer> listNode = new ArrayList<>();
        TreeNode tmpNode = node;
        Queue<TreeNode> queue = new LinkedList<>();

        queue.add(tmpNode);

        while (!queue.isEmpty()) {
            TreeNode peek = queue.poll();
            listNode.add(peek.val);

            if (peek.left != null) {
                queue.add(peek.left);
            }
            if (peek.right != null) {
                queue.add(peek.right);
            }
        }
        int[] res = new int[listNode.size()];
        int index = 0;
        for (Integer integer : listNode) {
            res[index++] = integer;
        }
        return res;
    }
}

class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;
    }
}